1. Field of the Invention
The present invention relates to devices for cooling integrated circuits. More specifically, the present invention relates to heat sinks and related devices.
While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
2. Description of the Related Art
Thermal control of electronic devices is important as heat affects functionality as well as reliability. Heat generation from semi-conductor devices, if not removed, can damage the device and cause catastrophic failure.
The trend in electronic cooling design is away from individual chips mounted on substrates and toward arrays of chips in a single pack. When the surface heat flux from the chips is large, a heat sink is needed to conduct heat from the chip. If there are many chips and little space, the chips are typically attached to a large area heat sink.
In order to remove heat generated by the chips efficiently, an improved conduction path for heat transfer between the chips and the heat sink is essential. The attachment of the heat sink directly to the chip has to be capable of handling differences in thermal expansion between different materials and the tolerances (variations in height) of multi-chip arrays. Hence, for mechanical type connections, the interface must be flexible.
Certain techniques are known in the art for providing improved conduction in heat transfer connections. For instance, U.S. Pat. No. 4,235,283 issued Nov. 25, 1980, to Gupta discloses a multi-stud module for removing the heat from the chip array. The disclosed module comprises a housing made of heat conducting material forming a cap over the circuit chips. The housing contains an opening at the location of each chip. Spring loaded studs are assembled in the openings. The studs become the heat conducting element with the end of each stud in contact with the associated chip.
Another conduction heat transfer connection is described in U.S. Pat. No. 4,156,458 issued May 29, 1979, to Chu et al. The connection comprises a heat conductive metallic foil bundle of sufficient thickness to contact the surface area of each chip for the required heat transfer. The connection is designed to be flexible enough to absorb the expansion and contraction due to temperature changes and the tolerance variations between the chips and the heat sink or a cold plate.
While numerous other heat transfer connections are known in the art, the conventional devices and methods are generally limited and may not solve some thermal design problems within the designer's cost and space limitations. Thus, a need remains in the art for further improvements in heat transfer connections, devices and mediums.